A superconducting quantum interference device system for geomagnetic archaeometry

A unique system for geomagnetic archaeometry is presented. It uses extremely sensitive supercon- ducting quantum interference devices (SQUIDs) as magnetic field sensors, laid out as intrinsic gradi- ometers. These sensors are mounted on a non-metallic cart, which guarantees smooth movement even at high speeds.Using a differential global positioning system (GPS) together with an inertial sys- tem the measured magnetic field gradient data are located on the mapped area with centimetre resol- ution and the height profile is also provided using the GPS. All data are stored in a data logger and partially online displayed on a laptop computer. At the time of this report, the system is pushed manually and has been tested on a Neolithic double ring ditch near Weimar, Germany. In a gateway through the rings, remains of palisades and buildings have been well resolved, confirming the high sensitivity of the SQUID-based system. An excavation at the ring ditch showed that material with enhanced susceptibility was the origin of the magnetic field gradient signals. Copyright # 2007 John Wiley & Sons, Ltd.